A conventional separable fluid coupling typically includes two separate fittings which may be suitably connected together or disconnected from each other for providing a sealed fluid through-channel when connected, while allowing the disassembly of attached components when disconnected. In order to effectively seal the fluid being channeled through the coupling from leaking therefrom, conventional couplings typically include elastomeric seals such as O-rings. However, such seals are typically life limited at relatively high temperatures experienced by the fluid coupling. For example, in a boiling water nuclear reactor vessel, high temperature water of about 518.degree. F. (270.degree. C.) is channeled within the vessel. At such a high temperature, a conventional fluid coupling disposed underwater in the vessel is not desirable in view of the typically low service life associated with the elastomeric seals.
Furthermore, the coupling typically includes screw threads which are used for assembling and disassembling the fittings thereof and is also formed of a suitable high temperature material such as conventional stainless steel. However, at the high temperature experienced, the threads are subject to slight corrosion which may cause the coupling fittings to freeze together which increases the difficulty of separating the coupling when desired.
Since a fluid coupling in a nuclear reactor vessel is typically located underwater, it is desirable to provide a fluid coupling which is relatively easily connected and disconnected underwater and from a distance by conventional tooling. For example, in one form of a nuclear reactor, an improved hydraulically driven turbine is being considered which may be used for controlling the conventional insertion and withdrawal of conventional control rods of the reactor. The turbine uses high pressure fluid, such as water, for driving the turbine in either of two opposite directions for controlling the position of the control rods. The turbine is located near the bottom of the nuclear reactor vessel under the high temperature water and is provided with its high pressure driving fluid through a suitable high pressure conduit. In order to allow improved maintainability of the turbine control rod drive, a suitable fluid coupling is desired within the high pressure conduit for allowing the coupling to be readily connectable and disconnectable from a considerable distance therefrom out of the reactor water while the coupling is positioned under the water.